<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div{
            background-color: aliceblue;
        }
    </style>
</head>
<body>
    <button>点击</button>
    <div>显示当前时间</div>
    <script>
        var btn = document.querySelector('button');
        var div = document.querySelector('div');
        btn.onclick = function(){
            div.innerText = getDate();
        }
        function getDate(){
            var date = new Date();
            var year = date.getFullYear();
            var month = date.getMonth()+ 1;
            var dates = date.getDate();
            var arr = ['星期天','星期一','星期二','星期三','星期四','星期五','星期六'];
            var day = date.getDay();
            return year + month + dates + arr[day];
            
        }
    </script>
</body>
</html> 